/*
** $Id: lbaselib.c,v 1.314.1.1 2017/04/19 17:39:34 roberto Exp $
** Basic library
** See Copyright Notice in lua.h
*/

#define lbaselib_c
#define LUA_LIB

#include "lprefix.h"

#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"

static int luaB_print(lua_State* L) {
  int n = lua_gettop(L); /* number of arguments */
  int i;
  lua_getglobal(L, "tostring");
  for (i = 1; i <= n; i++) {
    const char* s;
    size_t l;
    lua_pushvalue(L, -1); /* function to be called */
    lua_pushvalue(L, i); /* value to print */
    lua_call(L, 1, 1);
    s = lua_tolstring(L, -1, &l); /* get result */
    if (s == NULL)
      return luaL_error(L, "'tostring' must return a string to 'print'");
    if (i > 1)
      lua_writestring("\t", 1);
    lua_writestring(s, l);
    lua_pop(L, 1); /* pop result */
  }
  lua_writeline();
  return 0;
}

static int luaB_printe(lua_State* L) {
  int n = lua_gettop(L); /* number of arguments */
  int i;
  lua_getglobal(L, "tostring");
  for (i = 1; i <= n; i++) {
    const char* s;
    size_t l;
    lua_pushvalue(L, -1); /* function to be called */
    lua_pushvalue(L, i); /* value to print */
    lua_call(L, 1, 1);
    s = lua_tolstring(L, -1, &l); /* get result */
    if (s == NULL)
      return luaL_error(L, "'tostring' must return a string to 'print'");
    if (i > 1)
      lua_writestring_err("\t", 1);
    lua_writestring_err(s, l);
    lua_pop(L, 1); /* pop result */
  }
  lua_writeline_err();
  return 0;
}

#define SPACECHARS " \f\n\r\t\v"

static const char* b_str2int(const char* s, int base, lua_Integer* pn) {
  lua_Unsigned n = 0;
  int neg = 0;
  s += strspn(s, SPACECHARS); /* skip initial spaces */
  if (*s == '-') {
    s++;
    neg = 1;
  } /* handle signal */
  else if (*s == '+')
    s++;
  if (!isalnum((unsigned char)*s)) /* no digit? */
    return NULL;
  do {
    int digit = (isdigit((unsigned char)*s)) ? *s - '0' : (toupper((unsigned char)*s) - 'A') + 10;
    if (digit >= base)
      return NULL; /* invalid numeral */
    n = n * base + digit;
    s++;
  } while (isalnum((unsigned char)*s));
  s += strspn(s, SPACECHARS); /* skip trailing spaces */
  *pn = (lua_Integer)((neg) ? (0u - n) : n);
  return s;
}

static int luaB_tonumber(lua_State* L) {
  if (lua_isnoneornil(L, 2)) { /* standard conversion? */
    luaL_checkany(L, 1);
    if (lua_type(L, 1) == LUA_TNUMBER) { /* already a number? */
      lua_settop(L, 1); /* yes; return it */
      return 1;
    } else {
      size_t l;
      const char* s = lua_tolstring(L, 1, &l);
      if (s != NULL && lua_stringtonumber(L, s) == l + 1)
        return 1; /* successful conversion to number */
      /* else not a number */
    }
  } else {
    size_t l;
    const char* s;
    lua_Integer n = 0; /* to avoid warnings */
    lua_Integer base = luaL_checkinteger(L, 2);
    luaL_checktype(L, 1, LUA_TSTRING); /* no numbers as strings */
    s = lua_tolstring(L, 1, &l);
    luaL_argcheck(L, 2 <= base && base <= 36, 2, "base out of range");
    if (b_str2int(s, (int)base, &n) == s + l) {
      lua_pushinteger(L, n);
      return 1;
    } /* else not a number */
  } /* else not a number */
  lua_pushnil(L); /* not a number */
  return 1;
}

// Throw LUA_ERRRUN
static int luaB_error(lua_State* L) {
  int level = (int)luaL_optinteger(L, 2, 1);
  lua_settop(L, 1);
  if (lua_type(L, 1) == LUA_TSTRING && level > 0) {
    luaL_where(L, level); /* add extra information */
    lua_pushvalue(L, 1);
    lua_concat(L, 2);
  }
  return lua_error(L);
}

static int luaB_getmetatable(lua_State* L) {
  luaL_checkany(L, 1);
  if (!lua_getmetatable(L, 1)) {
    lua_pushnil(L);
    return 1; /* no metatable */
  }
  luaL_getmetafield(L, 1, "__metatable");
  return 1; /* returns either __metatable field (if present) or metatable */
}

static int luaB_setmetatable(lua_State* L) {
  int t = lua_type(L, 2);
  luaL_checktype(L, 1, LUA_TTABLE);
  luaL_argcheck(L, t == LUA_TNIL || t == LUA_TTABLE, 2, "nil or table expected");
  if (luaL_getmetafield(L, 1, "__metatable") != LUA_TNIL)
    return luaL_error(L, "cannot change a protected metatable");
  lua_settop(L, 2);
  lua_setmetatable(L, 1);
  return 1;
}

static int luaB_rawequal(lua_State* L) {
  luaL_checkany(L, 1);
  luaL_checkany(L, 2);
  lua_pushboolean(L, lua_rawequal(L, 1, 2));
  return 1;
}

static int luaB_rawlen(lua_State* L) {
  int t = lua_type(L, 1);
  luaL_argcheck(L, t == LUA_TTABLE || t == LUA_TSTRING, 1, "table or string expected");
  lua_pushinteger(L, lua_rawlen(L, 1));
  return 1;
}

static int luaB_rawget(lua_State* L) {
  luaL_checktype(L, 1, LUA_TTABLE);
  luaL_checkany(L, 2);
  lua_settop(L, 2);
  lua_rawget(L, 1);
  return 1;
}

static int luaB_rawset(lua_State* L) {
  luaL_checktype(L, 1, LUA_TTABLE);
  luaL_checkany(L, 2);
  luaL_checkany(L, 3);
  lua_settop(L, 3);
  lua_rawset(L, 1);
  return 1;
}

static int luaB_collectgarbage(lua_State* L) {
  static const char* const opts[] = {
      "stop",
      "restart",
      "collect",
      "count",
      "step",
      "setpause",
      "setstepmul",
      "isrunning",
      "onestep",
      NULL,
  };
  static const int optsnum[] = {
      LUA_GCSTOP,
      LUA_GCRESTART,
      LUA_GCCOLLECT,
      LUA_GCCOUNT,
      LUA_GCSTEP,
      LUA_GCSETPAUSE,
      LUA_GCSETSTEPMUL,
      LUA_GCISRUNNING,
      LUA_GCONESTEP,
  };
  int o = optsnum[luaL_checkoption(L, 1, "collect", opts)];
  int ex = (int)luaL_optinteger(L, 2, 0);
  int res = lua_gc(L, o, ex);
  switch (o) {
    case LUA_GCCOUNT: {
      int b = lua_gc(L, LUA_GCCOUNTB, 0);
      lua_pushnumber(L, (lua_Number)res + ((lua_Number)b / 1024));
      return 1;
    }
    case LUA_GCSTEP:
    case LUA_GCONESTEP:
    case LUA_GCISRUNNING: {
      lua_pushboolean(L, res);
      return 1;
    }
    default: {
      lua_pushinteger(L, res);
      return 1;
    }
  }
}

static int luaB_type(lua_State* L) {
  int t = lua_type(L, 1);
  luaL_argcheck(L, t != LUA_TNONE, 1, "value expected");
  lua_pushstring(L, lua_typename(L, t));
  return 1;
}

// similar with luaT_objtypename
static int luaB_typedetail(lua_State* L) {
  int t = lua_type(L, 1);
  luaL_argcheck(L, t != LUA_TNONE, 1, "value expected");
  if ((t == LUA_TTABLE || t == LUA_TUSERDATA) && luaL_getmetafield(L, 1, "__name") == LUA_TSTRING) {
    return 1;
  }
  if (t == LUA_TLIGHTUSERDATA) {
    lua_pushliteral(L, "lightuserdata");
  } else if (t == LUA_TFUNCTION) {
    if (lua_iscfunction(L, 1)) {
      lua_pushliteral(L, "cfunction");
    } else {
      lua_pushliteral(L, "luafunction");
    }
  } else {
    lua_pushstring(L, lua_typename(L, t));
  }
  return 1;
}

static int pairsmeta(lua_State* L, const char* method, int iszero, lua_CFunction iter) {
  luaL_checkany(L, 1);
  if (luaL_getmetafield(L, 1, method) == LUA_TNIL) { /* no metamethod? */
    lua_pushcfunction(L, iter); /* will return generator, */
    lua_pushvalue(L, 1); /* state, */
    if (iszero)
      lua_pushinteger(L, 0); /* and initial value */
    else
      lua_pushnil(L);
  } else {
    lua_pushvalue(L, 1); /* argument 'self' to metamethod */
    lua_call(L, 1, 3); /* get 3 values from metamethod */
  }
  return 3;
}

static int luaB_next(lua_State* L) {
  luaL_checktype(L, 1, LUA_TTABLE);
  lua_settop(L, 2); /* create a 2nd argument if there isn't one */
  if (lua_next(L, 1))
    return 2;
  else {
    lua_pushnil(L);
    return 1;
  }
}

static int luaB_pairs(lua_State* L) {
  return pairsmeta(L, "__pairs", 0, luaB_next);
}

/*
** Traversal function for 'ipairs'
*/
static int ipairsaux(lua_State* L) {
  lua_Integer i = luaL_checkinteger(L, 2) + 1;
  lua_pushinteger(L, i);
  return (lua_geti(L, 1, i) == LUA_TNIL) ? 1 : 2;
}

/*
** 'ipairs' function. Returns 'ipairsaux', given "table", 0.
** (The given "table" may not be a table.)
*/
static int luaB_ipairs(lua_State* L) {
#if defined(LUA_COMPAT_IPAIRS)
  return pairsmeta(L, "__ipairs", 1, ipairsaux);
#else
  luaL_checkany(L, 1);
  lua_pushcfunction(L, ipairsaux); /* iteration function */
  lua_pushvalue(L, 1); /* state */
  lua_pushinteger(L, 0); /* initial value */
  return 3;
#endif
}

static int load_aux(lua_State* L, int status, int envidx) {
  if (status == LUA_OK) {
    if (envidx != 0) { /* 'env' parameter? */
      lua_pushvalue(L, envidx); /* environment for loaded function */
      if (!lua_setupvalue(L, -2, 1)) /* set it as 1st upvalue */
        lua_pop(L, 1); /* remove 'env' if not used by previous call */
    }
    return 1;
  } else { /* error (message is on top of the stack) */
    lua_pushnil(L);
    lua_insert(L, -2); /* put before error message */
    return 2; /* return nil plus error message */
  }
}

static int luaB_loadfile(lua_State* L) {
  const char* fname = luaL_optstring(L, 1, NULL);
  const char* mode = luaL_optstring(L, 2, NULL);
  int env = (!lua_isnone(L, 3) ? 3 : 0); /* 'env' index or 0 if no 'env' */
  int status = luaL_loadfilex(L, fname, mode);
  return load_aux(L, status, env);
}

/*
** {======================================================
** Generic Read function
** =======================================================
*/

/*
** reserved slot, above all arguments, to hold a copy of the returned
** string to avoid it being collected while parsed. 'load' has four
** optional arguments (chunk, source name, mode, and environment).
*/
#define RESERVEDSLOT 5

/*
** Reader for generic 'load' function: 'lua_load' uses the
** stack for internal stuff, so the reader cannot change the
** stack top. Instead, it keeps its resulting string in a
** reserved slot inside the stack.
*/
static const char* generic_reader(lua_State* L, void* ud, size_t* size) {
  (void)(ud); /* not used */
  luaL_checkstack(L, 2, "too many nested functions");
  lua_pushvalue(L, 1); /* get function */
  lua_call(L, 0, 1); /* call it */
  if (lua_isnil(L, -1)) {
    lua_pop(L, 1); /* pop result */
    *size = 0;
    return NULL;
  } else if (!lua_isstring(L, -1))
    luaL_error(L, "reader function must return a string");
  lua_replace(L, RESERVEDSLOT); /* save string in reserved slot */
  return lua_tolstring(L, RESERVEDSLOT, size);
}

static int luaB_load(lua_State* L) {
  int status;
  size_t l;
  const char* s = lua_tolstring(L, 1, &l);
  const char* mode = luaL_optstring(L, 3, "bt");
  int env = (!lua_isnone(L, 4) ? 4 : 0); /* 'env' index or 0 if no 'env' */
  if (s != NULL) { /* loading a string? */
    const char* chunkname = luaL_optstring(L, 2, s);
    status = luaL_loadbufferx(L, s, l, chunkname, mode);
  } else { /* loading from a reader function */
    const char* chunkname = luaL_optstring(L, 2, "=(load)");
    luaL_checktype(L, 1, LUA_TFUNCTION);
    lua_settop(L, RESERVEDSLOT); /* create reserved slot */
    status = lua_load(L, generic_reader, NULL, chunkname, mode);
  }
  return load_aux(L, status, env);
}

/* }====================================================== */

static int dofilecont(lua_State* L, int d1, lua_KContext d2) {
  (void)d1;
  (void)d2; /* only to match 'lua_Kfunction' prototype */
  return lua_gettop(L) - 1;
}

// May Throw LUA_ERRRUN
static int luaB_dofile(lua_State* L) {
  const char* fname = luaL_optstring(L, 1, NULL);
  lua_settop(L, 1);
  if (luaL_loadfile(L, fname) != LUA_OK)
    return lua_error(L);
  lua_callk(L, 0, LUA_MULTRET, 0, dofilecont);
  return dofilecont(L, 0, 0);
}

static int luaB_assert(lua_State* L) {
  if (lua_toboolean(L, 1)) /* condition is true? */
    return lua_gettop(L); /* return all arguments */
  else { /* error */
    luaL_checkany(L, 1); /* there must be a condition */
    lua_remove(L, 1); /* remove it */
    lua_pushliteral(L, "assertion failed!"); /* default message */
    lua_settop(L, 1); /* leave only message (default if no other one) */
    return luaB_error(L); /* call 'error' */
  }
}

static int luaB_select(lua_State* L) {
  int n = lua_gettop(L);
  if (lua_type(L, 1) == LUA_TSTRING && *lua_tostring(L, 1) == '#') {
    lua_pushinteger(L, n - 1);
    return 1;
  } else {
    lua_Integer i = luaL_checkinteger(L, 1);
    if (i < 0)
      i = n + i;
    else if (i > n)
      i = n;
    luaL_argcheck(L, 1 <= i, 1, "index out of range");
    return n - (int)i;
  }
}

/*
** Continuation function for 'pcall' and 'xpcall'. Both functions
** already pushed a 'true' before doing the call, so in case of success
** 'finishpcall' only has to return everything in the stack minus
** 'extra' values (where 'extra' is exactly the number of items to be
** ignored).
*/
static int finishpcall(lua_State* L, int status, lua_KContext extra) {
  if (status != LUA_OK && status != LUA_YIELD) { /* error? */
    lua_pushboolean(L, 0); /* first result (false) */
    lua_pushvalue(L, -2); /* error message */
    return 2; /* return false, msg */
  } else
    return lua_gettop(L) - (int)extra; /* return all results */
}

static int luaB_pcall(lua_State* L) {
  int status;
  luaL_checkany(L, 1);
  lua_pushboolean(L, 1); /* first result if no errors */
  // pcall(0) func(1) ...(n) true(n+1)
  lua_insert(L, 1); /* put it in place */
  // pcall(0) true(1) func(2) ...(n+1)
  // lua_pcallk(L, argc, retc, errfunc, ctx, k)
  status = lua_pcallk(L, lua_gettop(L) - 2, LUA_MULTRET, 0, 0, finishpcall);
  return finishpcall(L, status, 0);
}

/*
** Do a protected call with error handling. After 'lua_rotate', the
** stack will have <f, err, true, f, [args...]>; so, the function passes
** 2 to 'finishpcall' to skip the 2 first values when returning results.
*/
static int luaB_xpcall(lua_State* L) {
  int status;
  int n = lua_gettop(L);
  luaL_checktype(L, 2, LUA_TFUNCTION); /* check error function */
  lua_pushboolean(L, 1); /* first result */
  lua_pushvalue(L, 1); /* function */
  // xpcall(0) func(1) msgh(2) ...(n) true(n+1) func(n+2)
  lua_rotate(L, 3, 2); /* move them below function's arguments */
  // xpcall(0) func(1) msgh(2) true(3) func(4) ...(n+2)
  // lua_pcallk(L, argc, retc, errfunc, ctx, k)
  status = lua_pcallk(L, n - 2, LUA_MULTRET, 2, 2, finishpcall);
  return finishpcall(L, status, 2);
}

static int luaB_tostring(lua_State* L) {
  luaL_checkany(L, 1);
  // luaL_tolstring(L, 1, NULL);
  int level = (int)luaL_optinteger(L, 2, 0); // when the second parameter is nil, the level will be 0
  luaL_tolstringex(L, 1, NULL, level);
  return 1;
}

static int luaB_atexit(lua_State* L) {
  luaL_checktype(L, 1, LUA_TFUNCTION);
  lua_settop(L, 1);
  luaL_atexit(L);
  return 0;
}

static int luaB_atrepl(lua_State* L) {
  luaL_checktype(L, 1, LUA_TFUNCTION);
  lua_settop(L, 1);
  luaL_atrepl(L);
  return 0;
}

static int luaB_cocall(lua_State* L) {
  luaL_checktype(L, 1, LUA_TFUNCTION);
  const int n = lua_gettop(L);
  lua_checkstack(L, 1);
  lua_State* co = lua_newthread(L);
  lua_insert(L, 1);
  lua_checkstack(co, n);
  lua_xmove(L, co, n);
  const int status = lua_resume(co, L, n - 1);
  if (status != LUA_OK && status != LUA_YIELD) {
    luaL_traceback(L, co, NULL, 0);
    fprintf(stderr, "luaB_cocall resume coroutine error: %s\n%s", lua_tostring(co, -1), lua_tostring(L, -1));
    lua_pop(L, 1);
  }
  lua_settop(co, 0);
  return 0;
}

static const luaL_Reg base_funcs[] = {
    {"assert", luaB_assert},
    {"collectgarbage", luaB_collectgarbage},
    {"dofile", luaB_dofile},
    {"error", luaB_error},
    {"getmetatable", luaB_getmetatable},
    {"ipairs", luaB_ipairs},
    {"loadfile", luaB_loadfile},
    {"load", luaB_load},
#if defined(LUA_COMPAT_LOADSTRING)
    {"loadstring", luaB_load},
#endif
    {"next", luaB_next},
    {"pairs", luaB_pairs},
    {"pcall", luaB_pcall},
    {"print", luaB_print},
    {"rawequal", luaB_rawequal},
    {"rawlen", luaB_rawlen},
    {"rawget", luaB_rawget},
    {"rawset", luaB_rawset},
    {"select", luaB_select},
    {"setmetatable", luaB_setmetatable},
    {"tonumber", luaB_tonumber},
    {"tostring", luaB_tostring},
    {"type", luaB_type},
    {"typedetail", luaB_typedetail},
    {"xpcall", luaB_xpcall},
    {"atexit", luaB_atexit},
    {"atrepl", luaB_atrepl},
    {"printe", luaB_printe},
    {"cocall", luaB_cocall},
    /* placeholders */
    {"_G", NULL},
    {"_VERSION", NULL},
    {"NULL", NULL},
    {NULL, NULL},
};

LUAMOD_API int luaopen_base(lua_State* L) {
  /* open lib into global table */
  lua_pushglobaltable(L);
  luaL_setfuncs(L, base_funcs, 0);
  /* set global _G */ // luaL_openlibs will set "_G" to global table again
  lua_pushvalue(L, -1);
  lua_setfield(L, -2, "_G");
  /* set global _VERSION */
  lua_pushliteral(L, LUA_VERSION);
  lua_setfield(L, -2, "_VERSION");
  lua_pushlightuserdata(L, NULL);
  lua_setfield(L, -2, "NULL");
  return 1;
}
